Vermont’s smart grid technology is considered to be one of the top five in the nation. These VELCO transmission lines are in Pittsford.

Vermont’s electrical grid is at a tipping point, experts say.

“We are in a period of unprecedented change at an accelerating rate,” says Kerrick Johnson, vice president for external affairs at the Vermont Electric Power Company, known as VELCO.

It’s not an isolated phenomenon. Vermont’s electrical grid is part of a New England-wide network of bulk-power generators and transmission lines operated by ISO New England. ISO stands for “independent system operator.” The New England network in turn is part of a larger regional grid that covers the eastern half of the country.

But Vermont does chart its own path, with laws passed by the state Legislature and regulatory decisions made by the Public Service Board — which acts as a sort of energy court. Vermont’s role as a national leader in net metering regulations and smart grid technology means that during this period of accelerating change, we have a seat in the front of the roller coaster.

Right now Vermonters are making important decisions about our electrical grid, but the grid itself is a mystery to many. Here is a brief overview of its most important aspects.

Smart meter versus smart grid

“The smart meter is the most visible component of the smart grid, but it’s not the most important component,” says Paul Hines, assistant professor at the University of Vermont School of Engineering and an expert on electrical grids.

It’s the use of digital technology to relay outage information, reroute power and even locate crews that makes the smart grid smart, he says.

Connectivity — as in the Internet — is at the heart of the smart grid, explains Greg White, vice president of field operations for Green Mountain Power, or GMP.

“It’s in all aspects of the electrical grid,” says White.

Customers can see this in the social networking tools that the company uses to communicate with them, he says, but there is even more of that behind the scenes. White says the focus has been on how the smart grid lets consumers make better choices, but better information means the utility itself can be more efficient.

Transmission versus distribution

To most of us, the poles and wires that bring electricity to our doorstep are all the same. But to people in the electrical industry, there is an important distinction.

Transmission lines move high voltages across long distances. In Vermont, VELCO operates the state’s transmission system. Distribution lines bring power to our homes and businesses and are owned and maintained by Vermont’s 17 electric distribution utilities.

Understanding the difference between transmission and distribution is vital to understanding the changes that are taking place in the grid.

Experts expect the distribution system to grow more complex, while the transmission system grows more robust to meet new federal requirements.

Net metering and distributed generation

It’s no accident that those small, local electrical generation projects are known as “distributed generation.” They connect to distribution lines, while major power plants connect to transmission lines.

Distributed generation may be the wind turbine you installed on your roof, or the small-scale community solar farm down the road.

“To the grid it looks like energy efficiency,” because it is produced and consumed in the same place, reducing input from the larger grid, says Darren Springer, deputy commissioner of the Public Service Department, the state agency that represents the public interest in energy issues.

“Distributed generation is exploding,” says VELCO’s Johnson, “not just in Vermont, but across the United States.”

Distributed generation requires distribution lines to run both ways — more like transmission lines. It also reduces the amount of power transmission lines need to carry, since more electricity is generated where it is used.

Net metering is the method used in Vermont to link distributed generation systems into the larger grid. Excess energy is sold to the local utility at the going rate. The state Legislature is considering a bill that will extend Vermont’s net metering law.

Integrating renewables

“Integrating wind and solar requires changes to the grid,” says Hines, “but we’re not going to tear it up and start new.”

The need for a multi-million dollar piece of equipment, a synchronous condenser, to fully integrate the Lowell wind project into the grid may have led some Vermonters to think that all renewable energy projects require expensive upgrades.

However, says Hines, “The synchronous condenser in Lowell is a particular solution to a particular problem — building a wind farm in a weak part of the grid.”

Adjustments must be made when any type of power plant goes on line. The real trick with renewables, Hines says, is balancing the electrical load when both solar and wind systems can slow down or stop producing power in an instant — as when a cloud passes in front of the sun.

When renewables wink off, says Ed McNamara, regional policy director for the Public Service Department, gas generation plants can start producing power in ten minutes.

The road to the future

“The challenge for Green Mountain Power is how to advance the system, while keeping reliability, costs and security,” White says of the test facing the state’s largest utility.

As for the challenges facing the Public Service Department, Springer comments, “Commissioner [Christopher] Recchia says that we’ve always had variable demand on the grid — people turning their lights on and off. The new opportunity and challenge is bringing clean, but intermittent, energy sources, like solar, into the grid.”

These challenges are large, but Hines, the nationally recognized expert, says Vermont can show the rest of the country the way.

“The grid could always be smarter. In Vermont, smart people worked hard to make it work well,” he says. “I think after the investment of the 2009 Recovery Act money in smart grid technology, Vermont is among the top five areas in the country for smart grid. If we do well, we get a chance to share it.”

Madeline Bodin is a freelance environmental journalist who lives in Andover. She can be contacted at madelinebodin+rh@gmail.com.